/*
 * Copyright (c) 2015. Rick Hightower, Geoff Chandler
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *  		http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * QBit - The Microservice lib for Java : JSON, WebSocket, REST. Be The Web!
 */

package io.advantageous.qbit.queue;

/**
 * Allows one to register callback methods for a queue.
 * created by rhightower on 2/10/15.
 *
 * @author Rick Hightower
 */
public interface QueueCallBackHandler {

    /**
     * Queue has reached its limit, can be the same as batch size for queue.
     * This is for periodic flushing to IO or CPU intensive services to improve throughput.
     * Larger batches can equate to a lot less thread sync for the hand-off.
     */
    default void queueLimit() {
        queueProcess();
    }

    /**
     * Notification that there is nothing else in the queue.
     */
    default void queueEmpty() {
        queueProcess();
    }


    /**
     * Callback for when the queue has started.
     */
    default void queueInit() {
    }

    /**
     * Callback for when the queue has started.
     */
    default void beforeReceiveCalled() {
    }


    /**
     * Callback for when the queue has started.
     */
    default void afterReceiveCalled() {
    }


    /**
     * Callback for when the queue is idle.
     */
    default void queueIdle() {
        queueProcess();
    }

    default void queueProcess() {

    }

    /**
     * Callback for when the queue is shutdown.
     */
    default void queueShutdown() {
    }

    /**
     * Callback for when the queue has just received some message.
     * idle can mean you are asleep with nothing to do.
     * startBatch can mean you just woke up.
     */
    default void queueStartBatch() {
    }

}
